Allied Telesis VERSION 5.4.3-2.6 manual BGP and BGP4+ Neighbor Route Filtering

BGP and BGP4+ Introduction

BGP and BGP4+ Neighbor Route Filtering

You can filter BGP and BGP4+ advertisements in two ways with neighbors:

■Use autonomous system path filters, as with the ip as-pathaccess-list (BGP and BGP4+) Global Configuration mode command and the neighbor filter-list (BGP and BGP4+) Router Configuration mode command

■Use access or prefix lists, as with the neighbor distribute-list (BGP and BGP4+) Router Configuration mode command.

If you want to restrict routing information that is learned or advertised, you can filter BGP routing updates to and from neighbors. You can define an access list or a prefix list and apply it to the updates.

To filter BGP routing updates for IPv4 routes, use the command below in Router

Configuration mode:

awplus(config-router)#

neighbor <neighborid> This command filters BGP routing updates to and from distribute-list<access-list>neighbors as specified in an access list for IPv4 routers in

{inout} Router Configuration mode.

To filter BGP4+ routing updates for IPv6 routes, use the command below in Address Family Configuration mode:

awplus(config-router-af)#

neighbor <neighborid> This command filters BGP routing updates to and from distribute-list<access-list>neighbors as specified in an access list for IPv6 routes in

{inout} Address Family Configuration mode.

BGP and BGP4+ Path Filtering by Neighbor

You can specify an access list filter on both incoming and outbound updates based on the BGP autonomous system paths. Each filter is an access list based on regular expressions. To specify the access list filter, define an autonomous system path access list and apply it to updates to and from particular neighbors.

To configure BGP path filtering, use the following commands starting in Global

Configuration mode:

awplus(config)#

ip as-pathaccess-list (BGP and	This command defines a BGP-related access list.
BGP4+)
awplus(config)#	This command enters Router configuration mode
router bgp <asn>
awplus(config-router)#	This command establishes a BGP filter for an IPv4 path in the
neighbor <neighborid>
filter-list <listname> {inout}	Router Configuration mode.

	Software Reference Supplement for SwitchBlade® x8112, x908, x900 and x610 Series Switches
C613-50032-01 REV D	AlliedWare PlusTM Operating System - Software Version 5.4.3-2.6	1.13